SKMaskFilter.CreateBlur and SKMaskFilter.CreateGamma issue

[SuperPotato45]

I'm struggling with some issue related to SKMaskFilter. I try to use Gamma, I found CreateGamma method available for SKMaskFilter. I want to apply this filter on whole SKBitmap. I tried something like code example in the documentation

     using (var skPaint = new SKPaint())
            {
                using (var maskFilter = SKMaskFilter.CreateGamma(Gamma))
                {
                    skPaint.MaskFilter = maskFilter;

                    using (var skCanvas = new SKCanvas(bitmap))
                    {
                        skCanvas.DrawBitmap(bitmap, new SKRect(0, 0, bitmap.Width, bitmap.Height), skPaint);
                    }
                }
            }

But this code doesn't work, I've tried SKMaskFilter.CreateBlur and it doesn't work as well. I discovered that CreateBlur is also available in SKImageFilter and when I used it this way it worked, but Gamma is not available in SKImageFilter. Am I doing something wrong or is it a bug?